Water tanks are widely used for storing rainwater collected from the roofs of residential houses, unit blocks and the like. Generally, at least one pipe is used to convey water, which is collected from the roof, so that said water flows off the roof and ultimately (usually down) through the pipe(s) and into the tank. The pipe(s) are typically themselves, or they may be connected to, one or more downpipes extending from the roofs guttering. Thus, rainwater that lands on the roof thereafter flows down off the roof into the roofs guttering. It then flows along the guttering to the nearest downstream location in the guttering where an opening in (or in the base of) the guttering connects to a downpipe. And from there, the water flows through the pipe(s) and ultimately into the tank, as described above.
Water flowing off roofs often contains contaminants like leaves, sticks, rubbish (e.g. plastic bags, wrappers, cigarette butts, litter, and other wind-blown debris) as well as other forms of debris. This can be especially so during the first or initial period(s) of rainfall that immediately follow periods of no rain (“dry spells”), because leaves, sticks, rubbish, etc, can accumulate on the roof during dry spells as there is no rainfall to wash them off. Having said this, the accumulation of leaves, sticks, rubbish, etc, on the roof does not necessarily only occur during long dry spells. This can also be a problem even during periods of regular rainfall (or even constant rainfall, e.g. as leaves and sticks may be blown onto the roof during storms, etc).
One of the ways of stopping or limiting contaminants, which may be contained or carried in any flow of water flowing from a roof, from entering the water storage tank, is to install a mesh at the tank's inlet. Such a mesh typically allows water to pass therethrough into the tank, but it prevents contaminants such as leaves, sticks, rubbish, etc, which are larger than the grade of the mesh, from entering the tank. Therefore, depending on the grade of the mesh (i.e. depending how fine the mesh is) the mesh may also prevent other smaller particulates, or even dust, carried by the water from entering the tank.
In the field of water filters, and particularly rainwater filters, operability of a rain water filter at (or the ability of the filter to accommodate) high flow rates of water passing through the filter is generally considered highly desirable. However, typically, rain water filters or catching devices that are operable at high rain water flow rates have comparatively inferior catchment efficiency. Catchment efficiency refers to the quantity of water captured in e.g. the rain water collection/storage tank (or other receptacle or container) after a rain water filtering or catching operation as a percentage or ratio of the total influent rain water. In other words, a high catchment efficiency means that a high proportion of the total influent contaminated water that enters the filter or catching device is filtered by the filter and ultimately captured in the collection/storage tank or receptacle (and only a small proportion of the total influent water is lost or at least not filtered and collected). On the other hand, a lower catchment efficiency implies that, of the total influent contaminated water that enters the filter or catching device, only a lesser proportion is actually filtered by the filter and ultimately captured in the collection/storage tank or receptacle (and a larger proportion of the total influent water is lost or at least not filtered and collected).
It was mentioned above that rainwater filters or catching devices that are operable at (or which are able to accommodate) high rain water flow rates typically have a comparatively lower catchment efficiency. In a related manner to this, rain water filters or catching devices that have high or very high catchment efficiencies are typically unable to operate at (or accommodate) high water flow rates. Therefore, there is apparently a need for rain water harvesting (filtering) devices that can operate at (or accommodate) high water flow rates and achieve comparatively high catchment efficiencies (or at least comparatively higher catchment efficiencies than is possible with most previous devices).
Another significant issue with rain water harvesting and filtration devices relates to filtration quality. While it is generally desirable to achieve a high quality of captured water (i.e. water wherein the level or amount of remaining contained debris or contaminants is low), in order to do so, such devices need to incorporate fine or very fine meshes or other forms of filters, so as to capture and remove debris and particulate matter that is equal to or above a very small size. Using such fine filter meshes (or other forms of fine filters) often results in a reduction in the catchment efficiency of the device because such filtration (and in particular the speed at which the water can pass through the fine mesh) is usually slower, and it can also results in regular or more frequent blocking or clogging of the filter as contaminants which are removed from water can remain and come to rest on the filter mesh, thereby blocking or clogging it up, which is highly undesirable. In order to overcome the issue of reduced catchment efficiency, filtration quality is often compromised (including intentionally, as a trade-off) by the use of filters which capture only relatively larger sized debris (i.e. debris and particulate matter that is equal to or above a relatively larger size). Therefore, there is apparently a further need for rain water catching or filtering devices that may enable fine filtration of rain water without significantly or severely reducing catchment efficiency.
Another highly desirable feature in rain water filters and catching devices is to reduce the incidences of blocking and/or clogging of the filters, preferably by incorporating a self-cleaning feature or functionality, so that said “self-cleaning” of the device (or its relevant parts or filters etc) may alleviate or reduce the need for regular (often manual) cleaning. In other words, self-cleaning may alleviate the need for users to regularly (manually) collect and remove debris that might otherwise have accumulated on the filtering surfaces of such devices and filters.
Thus, it appears that there has been a long felt need for a rain water harvesting or capturing device which is able to sufficiently (or at least to a greater degree than previously) balance the requirements of being operable at high flow rates and achieve comparatively high catchment efficiency whilst also achieving acceptable filtration quality with self-cleaning capability. It is also thought that there may be a need for a device wherein a user is able to choose or modify the features or functionality of the device depending on the specific requirements of the user in the intended application or installation.
It is to be clearly understood that mere reference herein to any previous or existing devices, apparatus, products, systems, methods, practices, publications or to any other information, or to any problems or issues, does not constitute an acknowledgement or admission that any of those things, whether individually or in any combination, formed part of the common general knowledge of those skilled in the field, or that they are admissible prior art.